The present invention relates to a switching device having a good isolation characteristic. The invention relates also to a method for improving the isolation characteristic of a switch unit of a switching device so as to improve the isolation characteristic of the switching device.
Referring to FIG. 1, a block diagram of a conventional RF Front-end having a switch unit is shown. As illustrated, the RF Front-end 10 is adapted for transmitting and receiving wireless signals, comprising an antenna unit 11, a switch unit 13, at least one receiving path 15, a transmitting unit 17 and a control unit 19, wherein the control unit 19 is electrically coupled with the switch unit 13 and the transmitting unit 17, and adapted to provide power supply to the switch unit 13, and to turn on/off the switch unit 13.
In actual application, the control unit 19 is electrically connected with the switch unit 13 through a power line 191 and a control line 193, wherein the control unit 19 provides a voltage Vcc to the switch unit 13 through the power line 191, and also provides a control signal to the switch unit 13 through the control line 193, thereby switching the operation mode of the switch unit 13.
In this embodiment, the control unit 19 can switch the switch unit 13. Thus, the antenna unit 11 is electrically connected to the transmitting unit 17 through the switch unit 13, so that the transmitting unit 17 can transmit a signal through the switch unit 13 to the antenna unit 11, driving the antenna unit 11 to transmit a wireless signal. The control unit 19 can also switch the switch unit 13, enabling the antenna unit 11 to be electrically connected to the receiving path 15 through the switch unit 13, so that the antenna unit 11 can transmit a received wireless signal through the switch unit 13 to the receiving path 15. Thus, the RF Front-end 10 can receive or transmit wireless signals.
The RF Front-end 10 enters standby mode when it is out of the wireless signal receiving or transmitting process. At this time, the control unit 19 does not provide the power supply voltage Vcc to the switch unit 13, thereby saving standby mode current consumption. Further, the switch unit 13 isolates the antenna unit 11, the receiving path 15 and the transmitting unit 17 at the standby mode.